Harmonic selective-ringing system for party-lines.



H. D. CURRIER. HARMONIG SELECTIVE RINGING SYSTEM FOR PARTY LINES.

APPLICATION FILED MAY 5, 1909.

955,253. Patented Apr. 19, 1910.

2 SHEETS-SHEET l.

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H. 1 GURRIER. v

HABMONIG SELECTIVE RINGING SYSTEM FOR PARTY LINES. APPLICATION FILED MAY 5, 1909.

Patented Apr. 19, 1910.

2 SHEETS-SHEET 2.

//7 vemar: ff/ram 0. Curr/Lek HIRAIYID. CURRIER, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR TO thereon as to used tocontrol the si' tion provides tune UNITED STATES PATENT oFFioE.

WESTERN ELECTRIC COMITANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

HARMONIC SELECTIVE-RINGING SYSTEM FOR iPARTY -LINEs.

Specification of Letters Patent.

Patented Apr. f9, 1910.

Application filed May 5, 1909. Serial No. 494,084.

To all whom it may concern:

Be it known that I, HIBAM D. CURRIER, citizen of the 'United States, residing at' Bloomfield, inthe county of Essex and State of New Jersey, have invented-a certain newv and useful Improvement in Harmonic Selective-Ringing Systems for Party-Lines, of which the following is in full, clear, concise, and exact description.

My invention relates to selective signaling systems, moreparticularly to systems in which the signal receiving devices are tuned to respond only to periodically varying currents of definite frequency, the object being to provide an improved system in which several signals may be selectively controlled with the minimum number' of separate sources of current:

I The invention will be especially applicable to telephone systems, and makes it possible, for example, for the operator to se ectively signal any one of four stations on a party line, by using one oftwo ringing enerators supplying currents of different and without the use of from the limbs of the meta cuit. 1

In my invention a bell or other signal responsive to current of. one polarity is so associated with a line at each of two stations be normally inoperatiye, the bells or signalsrat the two stations being, however, rversely connected in their res ective branches.- tlons tuned means are ic telephone cirprovided adapted,

in responseto pulsating currents of the same predetermined frequency, to,bring thesignals at said stations into operative relation to the circuit, whereby that signal adapted to respond to current of the polarity impressed upon line will be selectively oper ate l Considered broadl therefore, my invenmeans whereby two stations equipped .with ordinary polarized biased bells maybeselectively signaled over a single circuitwith current of a single frequency. I

Where four or more stations are connected with a single line the stations may, in ac cordance with my invention, be considered as divided into airs, each pair being equipped as alrea y described, the mea'ns nal circuits at the two stations of each pair eing tuned to respond requency, iground branches- At each of the two staductors, the rela s at of Fig.

frequency,

to current of a predetermined frequency ,difiering from that to which the correspond ing means of any other pair is tuned, whereby the frequency of current impressed upon the line determines the pair of signals which shall be brought into operative relation to the circuit and the polarity of the current determines which signal of the pair shall respond.

My invention may be readily understood by reference to the accompanying drawings which show embodimentsthereof as applied to telephone signaling systems. Y

Figure 1 shows my invention as applied to a system'in which the tuning of the signal circuit controlling means at the various stations is accomplished mechanically, and Fig. 2 shows my invention as applied to a sys- .tem in which the tuning is accomplished electrically. I

Referring to Fig. 1, a phone line circuit, together ofiice circuits involved in calling a desired station on said line, is shown. In both the substation and central office portions of the diagram the circuits are shown complete with respect to both signaling and talking. The structure and operation. of those features' of the circuits which relate to talking and central'ofiice si naling, bein standard and well understoo by those ski led in the art, are,'however, not herein detail. I

In the diagram the line shown is equip ed at each of the stations relay which preferably is connected in series with a condenser in a branch of the line constations 3, 4, 5 and 6 being designate as 7, 8, 9 and 10, respectively, and the condensers as 11, 12, 13 and 14, respectively. In the circuit shown the condensers in series with the relays also-constitute elements of the substation talkin circuit, but this is not, of course, essentia to my invention. The relays 7, 8, 9 and 10 four party telewith the central.

at the respective stations may be of any form adapted to respond to current of a redetermmed frequency. In the diagram 1 the relays shown are of the mechanically' tuned t pe, based upon the well known principle t at a vibrati'n body as, for example, a reed, has a definite natural or rate of oscillation, to which it tends to adhere when actuated byperiodic forces and to which it is particularly responsive and eflicient if the forces be in tune with its natural period. In the system of Fig. 1 the relays at the respective stations,

is mounted upon a'flat spring 17 or is otherwise so carried as to be subject to a suitable force adapted to hold it in its middle'position when at rest and to restore it when in action. A weighted arm 18 carried by the armature 16 lies normally between two pivoted arms 19 and 20, said arms preferably having considerable inertia. Contact springs 21 and 22, which may be carried by the arms 19 and 20, to engage with cooperating contacts 23 and- 24, respectively, whenthe armature rocks and causes the arm 18 to strike and tilt the arms. With this arrangement of parts it will be readily understood that a relay may be so made and adjusted that the movable element will have any desired predetermined natural period within practicable limits and that, when so made and adjusted, its energization by current of corresponding frequency will cause the armature to respond efiiciently and cause the arm 18 to oscillate and alternately strike the arms 19 and 20. As a result of this action, the springs 21 and 22 will be successively forced into engagement with their corresponding contacts 23 and 24, whereby, by virtue of the inertia of said longer period than the other is open, which pairs being connected in multiple with a ranch 25 and 26 leading through the bell, the circuit through said bell will be mainwhile the relay is in operation. y invention will be more readily understood if the stations on the line be conceived to be divided into pairs. For example, in the case of the four party line under consideration stations 3 and 4 may be considered as constituting one pair and stations 5 and 6 another. The relays at the stations constituting a air would with my invention be tuned to the same frequency, which frequency would be unlike that to which, the relays at any other pair of stations would be tuned, sothat current of a predetermined line would circuits at the two stations where the relays are so tuned as to respond thereto.

At the stations 3-, 4*, 5 and 6 signals 2?, 28, 29 and 30, respectively, are provided, which signals may be ordinary polarized biased bells, said bells being connected at each stationin the branch circuit 25 and 26 con trolled by the relays thereat. The bells at the stations of a pair, as, for example, stations 3 and 4 would be reversely associated with the line with respect to their polarity, that is hell 2? would be so connected as be responsive only to negative pulsatin current passing through it from one lim of the line, and bell 28 would be so connected as to be responsive to positive pulsating current from the same limb.

Referring to the central office portion of the system of my invention 31 and 82 are any suitable sources of pulsating current, the sources shown diagrammatically being the well known ringing generatonadapted to supply pulsating current of positive or negative character. The system shown being a four station system, two frequencies of current are required which, for purposes be assumed to be sixteen therefore, be adapted to supply positive and negative sixteen cycle current and generator 32 be adapted to supply positive and negative fifty cycle current. Y

33, 34, 35 and 36 are keys or switches in the operators connecting circuit whereby when the plug 38 is inserted in the jack 39 of the desired line signaling current of frequency and polarity adapted to selectively operate the signal at the desired station may, by the operation of the proper key, be impressed upon the line.

The operation of the system of my vention in- Let it be assumed that and 8 are adapted to respond is as follows: the relays 7 to pulsating sixteen cycles per second, and that the bells 27 and 28, respectively controlled by said relays, are respectively adapted to respond to negative and positive currents only. Also adapted to respond to pulsating-current havfrequency of fifty pulsations per second, and that the signals 29 and 30, respectively controlled by said relays, are respectively adapted to respond and positive currents only. -With the system shown the central ofiice o erator having received a call for station 0. 3 would insert calling cord an impressing negative puleating current from generator 31 upon the line,'which current would flow out upon the ring side of the line, pass through the relay ranches at all the stat-ions, and return over the tip side of the line to ground at the key. The relays 9 and 10, at stations 5 and 6, not being adapted to respond to sixteen c cle current, no change in the circuit conditions these stations would occur. The relays 7 and 8, being adapted to respond to sixteen cycle current, wouldcperate and close the circuits of the bells 2? and 28, thereby allowing a portion of the current to flow through hells. The bells 27 and 28 belet it be assumed that the relays 9 and 10 are to negative current having a frequency of l iso line to which relays tuning,

ing olarized biased bells so associated with the line that the former responds to negative current only and the latter to positive current, bell 28 will be unaffected by the flow through it of the negative current and bell 27 will be the only one of the four bells associated with the line to respond to the depression of ke 36. Thus the selective operation involve of the system of my garded as comprising the first of which is the response of the relays at two stations, and the consequent completion of the bellcircuits thereat, whereby the pair of stations, one of which is the de-. sired station, is selected; and the second of which is the response of that bell of the selectedpair adapted to operate oncurrent of the polarity used, whereby the desired station of the selected pair is signaled.

,If the call were for station No. 4 the operator would depress key 35 thereby impressing current upon the lineof the same frequency as in the case just described, but of positive polarity as a result of which the operations referred to above as constituting the first stage of the selective process would be identically as already set forth, the second stage, however, differing in that the use of posltive current would result in the actuation of bell 28 instead of bell 27. It will be understood that although, for convenience of discussion the operation is described as made up of two stages, there would, in actual practice, be no distinct stages, the bell at the desired station responding promptly to the depression of the proper key.

If the call were for station No. 5 the operator pressing fifty cycle negative current upon the line as a result of which, relays 9 and 10 would respond and complete the circuits of bells 29 and 30, relays 7 and 8 remaining inactive by reason of their not being adapted to respond to current of the frequency used. Bell 29 being so connected with the line as to respond to negative current, and bell 30 being reversely connected, the former would alone operate. v

If the call were for station No. 6 the operator would depress key 33, thereby impressing fifty cycle positive current upon the 9 and 10 and bell 30 would alone respond, as will be readily understood from the description already given.

invention may be re- In Fig. 2 my invention is shown embodied.

which is generally'simi-lar to that shown in Fig; 1 and diifers only in the method of the relays 7, 8, 9 and 10 are ordinary relays. The inductance of each of these rein signaling a given station.

two progressive steps,

lays, however, and the capacity of" the associated condenser are so related that the bridge circuit in which they are included is electrically tuned, so that the relay in any particular bridge circuit will respond only to current of the proper frequency. That is to say, in the system shown, the inductance of the relays 7 and 8- at the stations3 and 4 is so related to the capacity of the condensers 11 and 12, respectively, that the relays will respond only to pulsating current having a frequency of sixteen cycles per second. In a similar manner the circuits at the substations 5 and 6 are so arranged thatthe relays 9 and 10 will respond only to {pulsa-- tory current having a frequency of fi y cycles per second. The method in which this. electrical tuning is accomplishedysince it is well known intheart, need not be discussed at length, but it should be understood that my invention contemplates the use of either mechanically or electrically tuned means, or any combination of mechanical and electrical tuning which may be desired.

In the description of my invention the current used has been referred to as pulsating current having a frequency expressed in cycleseper second. The term pulsating is herein-used in its broad and usual sense as a current in which the average of the instantaneous values of the wave throughout aperiod or cycle is other than zero, as distinguished from alternating current in which said average is zero. In accordance with this definition of terms it will be understood that my inventlon contemplates the use of any pulsating. current as, for example,

.not onlypulsating current derived from a generator of the type shown diagramatically 111 the accompanying drawings, wherein, during a portion of the period, no current is delivered from the source, but current of any pulsating nature as, for example, current produced by superposing varying current upon constant current such as may be derived from an alternating current generator in series with a battery in which case the alternations are of unequal value.

Having described my invention, I claim: 1. The combination with a line, of signals at different stations'on said line ada ted to respond respectively to currents of difierent polarity, an electro-responsive device ateach station, responsive only to current of predetermined frequency, for controlling the circuit of the signal, tsaid station, the dc vices at the two stations being responsive to currents of the same frequency, a source of current for operating said devices and signals, and switches for impressing said current upon the line.

2. The combination with a line, of a relay, responsive only to current of predetermined frequency, at each of a pluralityof stations on said lme,-the relays at two of the stations being adapted to respond to currents of one frequency and the relays at another two stations being adapted to respond to currents of another frequency, a signal at each station controlled by the relay at said station, the signals, at each of said two stations, being adapted to respond respectively to currents of differentpolarity, sources of current for operating the relays and signals, and switches for impressing said current upon the line.

3. The combination with a line, of a mechanically tuned relay, responsive only to current of predetermined frequency, at each of four stations on said line, the'relays at two of said stations being adapted to respond to currents of one frequency, and the relays at the other two stations being adapted to respond to currents of another frequency, a signal in a branch of the line at each station, the signals at each of said two stations being adapted to respond respectively to currents of different polarity, sources of current for operating the relays and signals, and switches for impressing said current upon the line.

4. The combination with a telephone line, of a relay, responsive only to current of predetermined frequency, at each of four stations on said line, the relays at two of said stations being adapted to respond to currents of one frequency and the relays at the othei; two stations being adapted to respond to currents of another frequency, a bell at each station in a normally open branch of the line controlled by the relay at said station, the bells, at each of said two stations, being adapted to respond respectively to currents of different polarity, sources of current for operating the relays and bells, and switches for impressing said current upon the line.

In witness whereof, I, hereunto subscribe my name this 4th day of May A. D.. 1909.

' HIRAM D. CURRIER.

Witnesses EDGAR F. BEAUBIEN, IRVING MACDONALD. 

